There are lots of streetmarkets in Seoul with a large variety of foods. Some restuarants you should check out if you were to visit Seoul is Jungsik Dang, Hanilkwan, and Mingles. If you were to visit Seoul, I would highly recommend trying out the food because there is so much to try.
Korean BBQ
Typically, when you go to a korean barbeque spot, people sit around a table and grill different types of meat like pork, chicken, beef, etc. People also tend to drink soju or order dishes on the side as well. If you go to a korean bbq place, you will be able to try many different korean dishes such as samgyeopsal and bulgogi.
Kimchi Jjigae
This is commonly known as kimchi stew, which contains the staple in korean cuisine, kimchi. Along with kimchi, it has onions, tofu, scallions, seafood, or sometimes pork. It is served hot and it's a spicy dish with lots of pepper flakes that has a twist added with the fermented vegetables. Be sure to try this if you like spicy food!
Kimbap
Kimbap is a korean sushi roll that is usually eaten as a light snack. It contains rice with sesame oil that is mixed with other ingredients like spinach, carrots, crab sticks, radish pickles, cheese, etc. with an outer layer of dried seaweed. It varies based off of the kimbap you are eating. For instance, there is bulgogi, tuna, and samgak kimbap.
Tteokbokki
This popular street food dish is a spicy stirred fried rice cake dish. It's made from tteokmyeon and for it to be spicy, it is mixed with a gochujiang sauce. You can eat it as is or top it with scallions and boiled eggs. In addition, some people add sesame seeds on top of their tteokbokki as well. Soju is also a good pair with this dish since spicy foods go well with soju.